Create Way to Link to SharePoint Library or File

Building a form and newly using Nintex. Users have been saving forms to SharePoint libraries and folders for several years. One library for each year and below various folders with files including emails.

Need way, unsure how or best control to use, to let user select a particular library and file (or at least library) and save that path (?) link (?) in the form field to make it easy in future to get to that library and file. Going forward will simply attached files to a form as created. Considering converting long SharePoint URLs using google.com URL Shortener.

Hmm - well, the first idea that came to mind was to make a SharePoint list with a directory of all libraries that could be added - a column for the name (probably Title) and then one for the path, which you could then display via Calculated Field.

I suppose it depends how many libraries we're looking at here. If you have many and they change constantly then probably not a great idea.